SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b038fbd599ea6442957bc1268c83feeef07445c5072f4ab4124ba1b62bf73d83' 
  AND token = 'i/+xyTE0xwxN/JzTNCuSzZvtEdqbg8mnEallnkGmqU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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