SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90e7c4198beaadc2910d297c65390cbb8752c1783506c6499055d406156db5e4' 
  AND token = 'MvnbjPtZ32sGtU7NuZzcNvqMFCnhd6qw5sAOOYeDh64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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