SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7af511c10600cc5a2b2341540bbeec2eda05f671382df7bb5ff0bbd785a199a' 
  AND token = 'OdvNRjLswKRKL9gigsp3maR/9uDsU8//qaEtLGvmOno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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