SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e954e9be2782393713796b4ffcb396fef5d648694827e2244fc089fb85861fc7' 
  AND token = '0UYV5aEUyYqqRbHirnSJ6j/RiaZ1eHON/JU/zVAQDmA=' 
  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"
    }
  }
}