SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ff4d964a8be15925281afc994de75b996506aba8a4e7963b64e125363965dea' 
  AND token = '/kvsyU+lFjtoQKLrNpWXAIuttqTg82PLj/BiuIPGSKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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