SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b31d52ba73c00bca85cc413d096dfea226922932bf381bcb06746e3e86c30bae' 
  AND token = 'EIYY4ls3ygC+DNUO8Rq7ROjMLs3thGr98ZBcGa2ci5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}