SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47c5429fbdd2f472761b1b6e030af948ec98f9137d8df05b7e60bdbb6f4437c7' 
  AND token = '8oszYN10rGKtIGioT/gIeDdV+nVZmIygt6u+WPZqLss=' 
  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"
    }
  }
}