SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f98251e8ff20f03743e4df9d55b31888a2bf4caef4464f3d0362fd3eef3cd5e' 
  AND token = 'EuZW78yXI1sDuyyCgH3vE5/pqycPLsdCjm5ScjL0Hv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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