SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5a348b2fbf178b6f5b9b0999a8003bd144a36d53e7cce46496b1891816300b2' 
  AND token = 'jgCmLtqXpfMEIoFAFklMLMne+QAtPA7MMicNa5OkEow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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