SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84cb66a3d700d14a999236769e2053986d173deb4aa63ea8a0cce1c80e4f93ad' 
  AND token = 'GxMW+4rYZR/BOnpsW4sPP/rJrn/qMU9F2EnAeHUWt1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}