SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3131c4e549c9b16216dcb52c9e7cff9bef983e81642af5ed328a1e0d80425603' 
  AND token = 'nQCCA1rMYb/oP3kLNE0LLc5s3FZXQUeDkBIpSvVTyqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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