SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e69586d7431315686b7150dccdfec2e6a55067c48825aa8307e6a21059a5313d' 
  AND token = 'RVMBymfrk9wkbx/CFhP9zfeVKJerQdqhiqR1Z781k74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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