SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ad2db3bea8ded0640100498b1c344417e61894ecfcaee82e43b729adfcabac8' 
  AND token = 'H+hVp9tAx9vDRIeyHbVsMqyQ2pf1R9S3Nbh2EsjYW/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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