SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b85578c1b463279b25a33d5b228e5051d9e75e09343519e330ff368ec7d859a' 
  AND token = 'KpDvyXY9O1NsnB8IzZlbMq17U2ARV/qmI2fup94yDf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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