SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '541d2a4d7c403132d2a60da1deca580ebd5a07dc2a8d3877e038193f0fef6c15' 
  AND token = 'ayKo1QuhtIc8Xsl4YoMQyMVAEe1lFZwslNxpPg0w0zE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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