SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a033216039b9829b2778e3460d426e9cbcc925eeebe41f1900282da9b7e1e46e' 
  AND token = 'UiriYQXWPU1WnOmyU+ZSEeBXPRcCarxKwAGi61cxhBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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