SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a5cbf6581c06519ce14188ba2655ad4cc86bcdb8dabfb44f703523a0202a9d7' 
  AND token = 'jvCP+NyzoPVaxGLtA4y2+Cqm0p+LGoHGhoPSqpaZJVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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