SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c18e02b3153c2716e931637be3f6c9e9f256bf213493f398e165af6bed60259' 
  AND token = '2fqBd0zYmk4aoEmk1yoILMcQKKftO7RfZDC14nJMqOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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