SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6705019a872f89f47aaaa33bb521ce6f3b27098afe0139f57417eb1457dc4f20' 
  AND token = 'g9LVOMMtFvpgFKWmVjjUCCIIzhsnuGGh79DDJatr60U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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