SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53fe71f0331717d4fff5a8dacca00cc0b7ace1043176a262b9324b1a0cde6d03' 
  AND token = 'qJWC4R587BXAphcxZ1PDojKK+vzClnILNLUgPSwvUZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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