SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '04e3a62db0c9a48112215eb69fa3a1b47de318b5dc5297e0a65872dc75357120' 
  AND token = 'q6N/U5rO18L2VQkwigEKJSfaVFv2IJlT1OtvjZRR/kQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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