SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8abf10a6e5979f5d577e9cb6b2df3be7f5ae1559e84e74679b28bd76aa9e7677' 
  AND token = 'OT/WruPw7Viumh//8utok915TCMz7aKY1l/yp1z06Ck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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