SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90685190896f2983f5d2c4c705ce435d1cafb50bcb4204419ea2ff865b467fac' 
  AND token = 'HxOCd75UrJ02n2AYQ8sEwEgshwUFLca4kbe4PUfJvuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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