SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccebff99f98f8874d6c7bb565515ee3f61f39444fb4d219275dea6ae9521267f' 
  AND token = 'rlM3h9gWFHHHuC+TYJZ1n0zcdDdcdT8KEq4tPPNZvRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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