SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '451eacc76447d0c367b921372f94ca9318c360e9f56be7a9a77bee6bb4440b40' 
  AND token = 'qC3RBbu+XIDkgvZWQY24bvhnhlleybSBAj8XM5zm+VM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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