SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '977d70ff3411c68c45471d70c26c343db682edb090a96cfb2a5b3a98bf99f227' 
  AND token = 'lTpjfEfrBwFm3X0b+r/EFMi8tZsjBBz/pBUCAgXpKcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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