SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3150213c503d37bb7c20f9d9c05a370e8021e40955a2adf32546d8fe2a04fe72' 
  AND token = 'MAs5f9yYKfGXDgjHyvzMetW7aeKOSAZKJq6BDfljjzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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