SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a926fb24640459a3f206bd175ad528cec9de29b1755029c51ca949edee9fc9f8' 
  AND token = '99suOv3WJmzfU94KLS+uLzwaWgWyWm16R9lG2CRA7/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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