SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26e8da4bf354905da4ee01c701e603784ce8fbbb261127bace2de01bf8a48804' 
  AND token = 'wSeB64kD9xDMBIRhDkQ8u/AExEzBaU2xtRjtBfZ07jU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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