SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b731ddaad062dd86a6da0f4872c51b678cd00cac4e323ba7f5a946df12c80cad' 
  AND token = 'G/l5K3Ue6EsbbyWZzXw20CbOmaa9X94ksF4dzzEZn0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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