SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90acad01fc7bd1663eac4e6ec7eecdcebb4f022b4209455a5d88fb2cb8b6cf91' 
  AND token = 'Jmy7f82JKXpemsUTzwBN3j/n71vU7gH1+CLdRnavzEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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