SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c4efa170c51feec8b22ca6564ac4cecfb456b2c4cf9fa2e213ab834b7bf8615' 
  AND token = 'gEqYU5YFAaHNiWjGUVBjKmokfrLgEoIrjlKjNK6KUD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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