SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b250191f0c17278250cc2e250c8d12d47668b7386ab6eb2e3b1bbe9518115dff' 
  AND token = 'Ijc5AaAobsEvmfzA2QgW7zLfwt/sIH0ltpqA3N0Uw6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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