SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4f626e1dbb5bff3c35d237522b3098218736208cd558e8b9840c362a0d529c0' 
  AND token = 'JYLGlkyyVyer3sj71YJyX1s4/cbX5/U2SMn87CKEDz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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