SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b298b4ad37f96b1a324701b1086c85ffde93097533209898b28e29c27a8d936' 
  AND token = 'Er4jChOMWxV72ao+ls7Xoha0pS2Vish9YnnO3oNVdYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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