SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c368dd0b65628b0b7025d75d57f043db1b4a91acf782bb3076fcdfeeb74eeb2f' 
  AND token = 'fNIrqlrYexNu7fycubWx8wdjpYbtXtJBtrdc9yBNklI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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