SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d1a50836591c1d9c18868f74fe3d5f757b38e576d522bdb26865c8ed3b90a03' 
  AND token = '7m9h80hxClupSjzZW2kYPPMVUu0qe/ZwcpKLVvX2HNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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