SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55e23f37ad62908456939abe2aab83d09ecf8403314c650dbd774edffa1f07f3' 
  AND token = 'DhHqoXktzdquO99eigtXtzyNmlFc1QJ/aIlX1m9EAP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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