SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3714083ff8d2ae3584749b798f4ce6b01ae145d5f4b26edb8b78209bd5920696' 
  AND token = 'Y45qxn2cYwqS9Em6IDaIadjaxdht9ua7+JyVidcXw/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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