SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65c7a34c0df50170847df3e8bf7b755d5cb007ed18d13670b229e493346d687f' 
  AND token = '4EiWiDL1EBPqS8nIBytLdscQGwWEE5fz0epuBrmQ2Y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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