SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76cab67bc45ee75d086e0b7186bb915f8eb3591d1d94c97c813032d45715c0c8' 
  AND token = 'eOshPl7tfRSe6NZh+LElnqNUIFKV40gN5w2iGLAIJmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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