SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb91e742a985ed69aac9a841284b7ec795b7fbadedbc024e3000fd8be21ac2ab' 
  AND token = 'JWsc3Mz+CnkwWj8Z7pvDLzqasxLWvYDxzkUR1dXKFnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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