SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ec431df4102e7b0f92324343068dfe61dc34729aab6691d0c2838a41569b93be' 
  AND token = 'hd/URy7CHuvGMKAUQm6nE2H3YgffDo3SrXEAMkPWhFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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