SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdf57c66007181619b0faaeb3e08f239508ca790013f5067c39655584201417b' 
  AND token = 'G1j9oZvYPvmJkWdWggHLqInlHG6xsVMKEqRwBSGcozU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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