SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91e56afbfd69aa60853d1c605b789daf68a4504d05de91cd8221ae64b0175759' 
  AND token = 'kyNzzJd5+NygOd0t03feGf6ZErxDvjBZrkSUnyxykcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}