SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '468ce3273016f3af4905147c49a8ae1688f8405677fb510a0618d593428c6b07' 
  AND token = 'pGtR3Z4naJ+F+S6eiWeJIt5JrdORLLAvt8GqNoLpDqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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