SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02f8addd5ff74e96125e5c62461dcd1ca1583a9831635e721d539b25461ca7d8' 
  AND token = 'wcXOTT+AUtYRoCavCAC5jbCAfTMmHmHzVSHWMIAy7Eg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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