SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a50893d3bc00b665f0cf3d00c6c08ee6ea0631276a1d580e0f5859169ccfd291' 
  AND token = '3GppyZmQLipK6M+n+vRIJam53ohe1rz/KqbpFo5URA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00492

JSON explain

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