SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed16f2a155f24f4165f8b90fa4ac8253da0f059b870f7a617832d5060ab18311' 
  AND token = '1NszCb2yj8A2Ol51+SA8fr7GSatMNcuCWtuQvLgMoGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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