SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5cf2fcb01f37ef15cc4736d9d889a36516520d5531118d5b5bd7c89236edf5d' 
  AND token = 'QFOlpKxCl2+hDlCZ42xoYu2XpSJP5yKuG4lRSJT68q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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