SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17275703d7d7e0466e7769f0ea913d306f98fd76ca42d3d3116bcdda02587a24' 
  AND token = '71Q1lvBGLVnl/9e5yWibrmEgPHk8fH39MBls1EGbW2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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