SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51195ea26bf2807929eb2d38087a323e644e472328957d3cb2478127c53b70c0' 
  AND token = 'EGY6XX+vrqNKRql5kBk+iTpe7ED+sZZAOFicpnv6cDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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