SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf56f9aecbbb7abf005cec5c8db23f31fe08666ed27d369593e33d2b72e5874b' 
  AND token = 'p4cOBRlq0+QNiDXU8bICqCQSoN1QjeSXCkFPDLkF8s4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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