SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed8a0b836f39ed38816787b8dbcb225c5940d25374817ad1dd0b48cfcf1c3645' 
  AND token = 'hutCqivugjHhXqjZG2Yf9tXTnst4bQDWZ4K05VGYXuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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