SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b27f432fb4ad552aed3c74d81b8bc4d3ecdbd497d0036aa57512e97a927996a6' 
  AND token = 'T3UVrwxjqjgmHKTQ4bKJy+RwIc9+Ae/jUsML5CDwMD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}