SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e475deb7b5eef928740b04edb5a1b7673615ebc8d99bc7647340a5417f3088f6' 
  AND token = 'sTMmwz8Wu8zYWnvEH4usw8a9pHDESCaFxZiP+211cSE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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