SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04c36f178a077d7abb8d57cccd4dcbabdcdf16ec73f001b7c6daca986a5707d6' 
  AND token = 'ian/rIsOdgwc68w0LBLGKhp84MlvJyqF6HWQJltuUlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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