SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e7939563a033c82b8a5a3f044509cab069ca4a243045de9e058db258c0aaabf' 
  AND token = 'mMF1txUnnFP5AoUEmVdnEvO+OHpNiHRg4oKGhIYj1as=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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