SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d865040845647466dceacbc897d1b70501b82456ebff3b8c90a723e7d1f883c' 
  AND token = 'N4arNCYekUTom3CawIFgRu3+PPdslTRe+n66BCpRBgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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