SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ae2f3912af633df5291717ea4410a976cf7a0837f94a42ee9d9063e9713769d' 
  AND token = 'u+posEd/j3Ntvvm4JUXpV+bHPqTBl5mpxI9FyCDHqsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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