SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f7aa4bbbd681d3f2dd9474fc1b3770982077a412905eb32fd1340012efe37b7' 
  AND token = 'I4a2zqHlPeD6ElGKLwsYENP+Kn3itBmPeeJEMdsdQ9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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