SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f204b0856af5b01ebaa4ec30d71661111e145f1709bbaf410f48d9d448b4fed' 
  AND token = 'UjJ40o6LMYzx4t0UstU4byKatJdFbE1b25U42qXcat8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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