SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd59312649b8610ec85699ddb569a0794ae95467c9a1dc4ac08d1624f118d3f73' 
  AND token = 'L63bXFi3q5KsOGNCswKmtjEBvowVPZCC6WnflewloBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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