SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '375f4b04367cc945c42b38d7067efa81a1c7d3d7df28e5e0da7741f15c4a8c53' 
  AND token = 'SnRuxZOPG+eh+V/c8E/IPDhbxz3+I9RWOfdEsrUQqs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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