SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75105241e0d0f9854c0a89ca97e33deb1d7da0f4579b4cbe92d7edd9fcd02043' 
  AND token = 'MATmrbeobF1wBGXLDNDpWD7iLurDYkEAxew3zGAaA4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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