SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c87582bb19ac3f57f70c39b58c07f58d3e44bad7755c3d5df6e67eee74af8a2e' 
  AND token = 'CcxevCnj+hSqexBHW4G+jlY27mFwyU3+JaMSazWgOGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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