SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1305f15d9351ed06fe50db629bb551cdf68e1ad8518c3e7f2e1f894252aca790' 
  AND token = 'YR13zTrgM8EbYjPHeQZlI3fkVBOatLECy5A352jmLy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}