SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c65ffc6f90928846d514a2d15d3fdce456ff0826a2370dedcdec22721bd7ed8' 
  AND token = '1gRmo5w+rm/APeDyTj1MKFfVQzR1wb4ybZ664RyHtO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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