SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '731207e75463dfba478f8b9562e7cb4e8b612b9af06b631a9fa5e31e9d08a0dd' 
  AND token = 'kqjUu8vyzwkTXzsC1oR+CXjnd5kXj3ATW+geraLRnp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}