SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48073b50e9a0f01452db8fd9756f8885f04e188a0b3aafee16013931a9c0107f' 
  AND token = 'd/6MwlhOddUa5i40u6/g5zblhX5g+OamGG5OJNV7f/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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