SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6325cdebb2e92a7f5941dc74e48727813af3c043f656173f3ccdc8ea3dec0f53' 
  AND token = 'eE4M2s9eakbA41b1baB7RwF8TTjhV1QgVAub3Jaw5Bc=' 
  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"
    }
  }
}