SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de2dd1d25ab3bafe91ccbb8d3ff2783a513fff402d5d3746000d5a8791bd4c9a' 
  AND token = 'BVH3xWl6FPXQ15jJs0wMahg4I/DNu6ISaC+zs4RdhQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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