SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '524b53caea78347ed2cb2a6302769d33d968ca7352cdcd9564eacda9c0363e74' 
  AND token = 'IK6OqiSxyzrWVzrkREy6d3Zaj/j0ekQgJog3UIb6Hmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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