SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '698a9df7299129428478cb6c6989d7889311df5e43d937471381c975e71654e5' 
  AND token = 'yd8ARfu3JRHpl97QJmLgbl/6tJguVvpI/sYjJ47OJr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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