SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd244309c28d6bb023e254ca040c4b329d66c9a9144eff7acf14e61529359450e' 
  AND token = 'RGVkZN66G4ubDGJ8h6BEk3iDgxUaJaVD6ILRGGmgmOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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