SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd318b031ec59bc81ef8063382a808c23fffcbd6549da72afd56bb5b5e50e20f9' 
  AND token = 'HZOhGFvi3CvVpnVNHNg9dF1UHVEPiMr8YSikzO+Ta94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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