SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5502dcab297066e21517aeac2512fd44324c2b98f8829007ff7101e4b656599' 
  AND token = 'H6jktVszYtWD3U+irmJEN1/SzdrWWfvdfmohz5pw7nQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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