SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70a976845beaad792361d49dd7bebfa985183f25772d6023e51382863bdc6404' 
  AND token = 'IDwCnbRvRARNR+YPVjUmx0DLdEPmskFR0BEqx9aMRrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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